Variable thermal capacity charge air cooler

ABSTRACT

Methods and systems are provided for variable thermal capacity charge air cooler (VTC-CAC). In one example, the VTC-CAC includes a plurality of cooling channels and an integrated bypass that diverts air around the cooling channels. Division of boosted intake air between the cooling channels and the bypass is regulated by a positioning of dual-gate mechanism that is adjusted in response to manifold charge temperature.

FIELD

The present description relates generally to methods and systems for acharge air cooler configured to adjust air flow through the cooler.

BACKGROUND/SUMMARY

A charge air cooler is often included in a boosted engine system toimprove a combustion efficiency of the engine. Intake air entering theengine may be compressed, or boosted, by a turbocharger compressor priorto combustion, resulting in an increase in temperature of the air. Thewarmed air may be channeled through the charge air cooler (CAC) to coolthe air before the being delivered to an intake manifold for subsequentmixing with fuel followed by ignition of the mixture at the enginecylinders. Cooling the boosted air increases its density so that agreater number of air molecules are introduced to the cylinders per unitvolume of air, resulting in a proportional increase in a power output ofthe engine that is derived by combustion of the air-fuel mixture.Furthermore, cooling the boosted air decreases the amount of NO_(x)emitted as a combustion product and reduces a likelihood of engine knockwhich may otherwise lead to degradation of engine performance.

The CAC, also known as an intercooler or aftercooler, is a heat exchangedevice formed from a thermally conductive material such as aluminum oranother type of metal. A surface of the CAC is often arranged in a frontcompartment of a vehicle, perpendicular to air flow generated duringvehicle navigation, to facilitate air-to-air cooling of the boosted airpassing through the CAC. The CAC is often configured with alternatingrows of tubes and fins that are held together by two headers plates withtanks welded to the headers. The tubes may be fluidly coupled at eitherend to one of the tanks so that air delivered to a first, inlet tank ischanneled through the tubes, combined at a second, outlet tank andreleased from the CAC to be delivered to the intake through an intakepassage. The fins may increase a surface area of the CAC that comes intocontact with the cooling cross-air flow. Heat is thus transferred fromthe warm boosted air, to the cooler surfaces of the CAC tubes which are,in turn, cooled by ram air and the engine cooling fan.

The cooling of the boosted air, however, may lead to condensationissues. For example, in humid climates, a temperature of the relativelymoist air cooled by the CAC may fall below a dew point of the air. Thismay result in water droplets condensing within channels of the CAC, theintake passage, or intake manifold. During periods of high boost demanddriving increased air flow through the CAC, the water droplets may bepurged into the engine cylinders during an intake cycle of thecylinders, leading to misfiring at the cylinders or hydrolock.

In addition, cooling the boosted air below a threshold, such as the dewpoint, may lower a manifold charge temperature of the engine. Whilelower charge air (e.g. boosted air ignited at the engine cylinders)temperature may enhance engine performance and reduce NO_(x) emissions,a concomitant decrease in combustion temperature may lead to undesirablyhigh levels of carbon monoxide and hydrocarbon discharged from theengine exhaust.

Other attempts to address overcooling of air flowing through the CACinclude adapting the engine with a bypass system to allow warmed air toreach the intake manifold. One example approach is shown by Tussing etal. in U.S. Pat. No. 7,007,680. Therein, a bypass line diverts boostedair around a charge air cooler. Air flow through the bypass iscontrolled via a bypass valve that is actuated by a bypass controller.The bypass controller is configured to operate the bypass valve based onan intake manifold temperature and the bypass valve includes rotatablevalve plates that are actuated by a device such as a solenoid or motor.Warmed air is diverted around the CAC and mixed with air exiting the CACto maintain the temperature of the intake manifold above a dew point.

However, the inventors herein have recognized potential issues with suchsystems. As one example, when at least a portion of the intake air isdiverted to the bypass around the CAC, the amount of air passing throughthe CAC is proportionally reduced. The air is sent to all channels ofthe CAC which are exposed to ram air (and fanned air) at ambienttemperature. During low mass flow rates, a temperature differencebetween the bypassed air and cooled air may be increased due to longercontact between air molecules and cooling surfaces of the CAC channels,thus decreasing the modulating effect of the bypassed air on themanifold charge temperature (MCT). Furthermore, regulation of air flowbetween the bypass and CAC channels may introduce undesirable complexityof control by burdening the system with additional sensors and valves.

In one example, the issues described above may be addressed by a coolingsystem of an engine comprising an intake passage configured to deliverboosted air to an intake manifold of the engine, a charge air cooleradapted to received boosted air from the intake passage via an inlet andreturn boosted air to the intake passage via an outlet, and the chargeair cooler comprising an integrated bypass, a plurality of coolingchannels, and a dual-gate mechanism including a first gate dividing theintegrated bypass from the plurality of cooling channels and a secondgate dividing the plurality of cooling channels into open channels andblocked channels, the blocked channels fluidically blocked fromreceiving intake air. In this way, the MCT may be regulated by a singledevice actuated in response to output from sensors already existing inthe engine system.

As one example, the variable thermal capacity charge air cooler(VTC-CAC) may be adapted with an integrated bypass and a dual-gatemechanism that portions air flow between the integrated bypass and thecooling channels of the VTC-CAC. The dual-gate mechanism is arranged ina header tank of the VTC-CAC and comprises a first sliding gate thatadjusts a number of cooling channels open to air flow and a secondswinging gate that moderates an opening to the bypass. Movement of bothgates is caused by a rotating screw that extends across the header tankand includes different thread pitches to achieve a difference in a speedof movement between the first and second gates (e.g., the first slidinggate may move along a first section of the rotating screw that has afirst thread pitch and the second swing gate may move along a secondsection of the rotating screw that has a second thread pitch, differentthan the first thread pitch). By adapting an engine system with theVTC-CAC, the MCT may be controlled using a single inexpensive device,and a likelihood of condensation forming and/or accumulating within theintake passage or intake manifold is reduced.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example engine system including acharge air cooler.

FIG. 2 shows an example of a variable thermal capacity charge air cooler(VTC-CAC) including an integrated bypass and a dual-gate mechanism.

FIG. 3 shows a front view of a sliding gate of a VTC-CAC.

FIG. 4 shows a perspective view of a dual-gate mechanism in a VTC-CAC.

FIG. 5 shows a perspective view of a dual-gate mechanism in a VTC-CACfrom a different angle.

FIG. 6 shows a perspective view of a hinged gate in a VTC-CAC.

FIG. 7A shows an example of a VTC-CAC with a dual-gate mechanism in afirst position.

FIG. 7B shows an example of a VTC-CAC with a dual-gate mechanism in asecond position.

FIG. 7C shows an example of a VTC-CAC with a dual-gate mechanism in athird position.

FIG. 8 shows an example routine for adjusting a VTC-CAC in response toMCT.

FIGS. 2-7C are shown approximately to scale.

DETAILED DESCRIPTION

The following description relates to systems and methods for a variablethermal capacity charge air cooler (VTC-CAC) to control a manifoldcharge temperature (MCT) and reduce a likelihood of condensation formingin an intake passage or intake manifold. The VTC-CAC may be included inan engine system, such as the exemplary engine system shown in FIG. 1.An embodiment of the VTC-CAC, illustrated in FIG. 2 in a cross-section,may be configured with an integrated bypass and a dual-gate mechanismarranged in a header tank of the VTC-CAC and actuated by a steppermotor. The dual-gate mechanism comprises a sliding gate that controls anamount of cooling channels open to air flow as well as a hinged gatethat adjusts air flow through the integrated bypass. The sliding gate isshown in detail from a front view in FIG. 3 and its positioning abovecooling channels of the VTC-CAC and coupling to a rotating screwcontrolling a movement of the sliding gate is shown from two differentperspectives in FIGS. 4 and 5. A positioning of the hinged gate is alsoshown in FIGS. 4 and 5. A perspective view of the hinged bypass gate anda spherical bearing, providing a self-aligning property, disposed in thehinged bypass gate is shown in FIG. 6. Movement of the both the slidinggate and hinged gate, from a fully open position of the hinged gate,through a partially open position, to a fully closed position of thehinged gate is shown in FIGS. 7A-7C in cross-sections of the VTC-CAC. Amethod for adjusting the dual-gate mechanism of the VTC-CAC in responseto the MCT is depicted in FIG. 8.

FIG. 1 is a schematic diagram showing an example engine system 100,including an engine 10, which may be included in a propulsion system ofan automobile. The engine 10 is shown with four cylinders 30. However,other numbers of cylinders may be used in accordance with the currentdisclosure. Engine 10 may be controlled at least partially by a controlsystem including controller 12, and by input from a vehicle operator 132via an input device 130. In this example, input device 130 includes anaccelerator pedal and a pedal position sensor 134 for generating aproportional pedal position signal PP. As such, the pedal positionsignal may indicate a tip-in (e.g., sudden increase in pedal position),a tip-out (e.g., sudden decrease in pedal position or release of theaccelerator pedal), and additional driving conditions.

Each combustion chamber (e.g., cylinder) 30 of engine 10 may includecombustion chamber walls with a piston (not shown) positioned therein.The pistons may be coupled to a crankshaft 40 so that reciprocatingmotion of the piston is translated into rotational motion of thecrankshaft. Crankshaft 40 may be coupled to at least one drive wheel 55of a vehicle via an intermediate transmission system 150. Further, astarter motor may be coupled to crankshaft 40 via a flywheel to enable astarting operation of engine 10.

Combustion chambers 30 may receive intake air from intake manifold 44via intake passage 42 and may exhaust combustion gases via exhaustmanifold 46 to exhaust passage 48. Intake manifold 44 and exhaustmanifold 46 can selectively communicate with combustion chamber 30 viarespective intake valves and exhaust valves (not shown). In someembodiments, combustion chamber 30 may include two or more intake valvesand/or two or more exhaust valves.

Fuel injectors 50 are shown coupled directly to combustion chamber 30for injecting fuel directly therein in proportion to the pulse width ofsignal FPW received from controller 12. In this manner, fuel injector 50provides what is known as direct injection of fuel into combustionchamber 30; however it will be appreciated that port injection is alsopossible. Fuel may be delivered to fuel injector 50 by a fuel system(not shown) including a fuel tank, a fuel pump, and a fuel rail.

Intake passage 42 may include throttle 21 having a throttle plate 22 toregulate air flow to the intake manifold. In this particular example,the position (TP) of throttle plate 22 may be varied by controller 12 toenable electronic throttle control (ETC). In this manner, throttle 21may be operated to vary the intake air provided to combustion chamber 30among other engine cylinders. In some embodiments, additional throttlesmay be present in intake passage 42, such as a throttle upstream of thecompressor 60 (not shown).

Further, in the disclosed embodiments, an exhaust gas recirculation(EGR) system may route a desired portion of exhaust gas from exhaustpassage 48 to intake passage 42 via EGR passage 140. The amount of EGRprovided to intake passage 42 may be varied by controller 12 via EGRvalve 142. Under some conditions, the EGR system may be used to regulatethe temperature of the air and fuel mixture within the combustionchamber. FIG. 1 shows a high pressure EGR system where EGR is routedfrom upstream of a turbine of a turbocharger to downstream of acompressor of a turbocharger. In other embodiments, the engine mayadditionally or alternatively include a low pressure EGR system whereEGR is routed from downstream of a turbine of a turbocharger to upstreamof a compressor of the turbocharger. When operable, the EGR system mayinduce the formation of condensate from the compressed air, particularlywhen the compressed air is cooled by the charge air cooler, as describedin more detail below.

Engine 10 may further include a compression device such as aturbocharger or supercharger including at least a compressor 60 arrangedalong intake manifold 44. For a turbocharger, compressor 60 may be atleast partially driven by a turbine 62, via, for example a shaft, orother coupling arrangement. The turbine 62 may be arranged along exhaustpassage 48. Various arrangements may be provided to drive thecompressor. For a supercharger, compressor 60 may be at least partiallydriven by the engine and/or an electric machine, and may not include aturbine. Thus, the amount of compression provided to one or morecylinders of the engine via a turbocharger or supercharger may be variedby controller 12.

Further, exhaust passage 48 may include wastegate 26 for divertingexhaust gas away from turbine 62. Additionally, intake passage 42 mayinclude a compressor bypass valve (CBV) 27 configured to divert intakeair around compressor 60. Wastegate 26 and/or CBV 27 may be controlledby controller 12 to be opened when a lower boost pressure is desired,for example. For example, in response to compressor surge or a potentialcompressor surge event, the controller 12 may open the CBV 27 todecrease pressure at the outlet of the compressor 60. This may reduce orstop compressor surge.

Intake passage 42 may further include charge air cooler (CAC) 80 (e.g.,an intercooler) to decrease the temperature of the turbocharged orsupercharged intake gases. In some embodiments, charge air cooler 80 maybe an air to air heat exchanger. In other embodiments, charge air cooler80 may be an air to liquid heat exchanger. Hot charge air from thecompressor 60 enters the inlet of CAC 80, cools as it travels throughCAC 80, and then exits to pass through the throttle 21 and then enterthe engine intake manifold 44. Ambient air flow from outside the vehiclemay enter engine 10 through a vehicle front end and pass across CAC 80,to aid in cooling the charge air. Condensate may form and accumulate inCAC 80 when the ambient air temperature decreases, or during humid orrainy weather conditions, where the charge air is cooled below the waterdew point. Condensate may also accumulate in the intake passage 42downstream of CAC 80, as well as in the intake manifold 44 as a resultof cooling intake air below the dew point. Furthermore, a temperature ofthe charge air, e.g. compressed air cooled by the CAC 80, may decrease amanifold charge temperature (MCT) to an extent where engine performancemay be degraded. Thus CAC 80 may be adapted as a variable thermalcapacity charge air cooler (VTC-CAC), described herein with reference toFIGS. 2-7C.

Controller 12 is shown in FIG. 1 as a microcomputer, includingmicroprocessor unit 102, input/output ports 104, an electronic storagemedium for executable programs and calibration values shown as read onlymemory chip 106 in this particular example, random access memory 108,keep alive memory 110, and a data bus. Controller 12 may receive varioussignals from sensors coupled to engine 10 for performing variousfunctions to operate engine 10, in addition to those signals previouslydiscussed, including measurement of inducted mass air flow (MAF) frommass air flow sensor 120; engine coolant temperature (ECT) fromtemperature sensor 112, shown schematically in one location within theengine 10; a profile ignition pickup signal (PIP) from Hall effectsensor 118 (or other type) coupled to crankshaft 40; the throttleposition (TP) from a throttle position sensor, as discussed; andabsolute manifold pressure signal, MAP, from sensor 122, as discussed.Engine speed signal, RPM, may be generated by controller 12 from signalPIP. Manifold pressure signal MAP from a manifold pressure sensor may beused to provide an indication of vacuum, or pressure, in the intakemanifold 44. Note that various combinations of the above sensors may beused, such as a MAF sensor without a MAP sensor, or vice versa. Duringstoichiometric operation, the MAP sensor can give an indication ofengine torque. Further, this sensor, along with the detected enginespeed, can provide an estimate of charge (including air) inducted intothe cylinder. In one example, sensor 118, which is also used as anengine speed sensor, may produce a predetermined number of equallyspaced pulses every revolution of the crankshaft 40.

Other sensors that may send signals to controller 12 include a manifoldcharge temperature (MCT) sensor 124 in the intake manifold 44, and aboost pressure sensor 126. Other sensors not depicted may also bepresent, such as a sensor for determining the intake air velocity at theinlet of the charge air cooler, for measuring charge air temperature atthe CAC outlet, and other sensors. In some examples, storage mediumread-only memory 106 may be programmed with computer readable datarepresenting instructions executable by microprocessor unit 102 forperforming the methods described below as well as other variants thatare anticipated but not specifically listed.

In some examples, engine system 100 may be a hybrid engine system withmultiple sources of torque available to one or more vehicle drive wheels55. In other examples, engine system 100 is a conventional engine systemwith only an engine, or an electric engine system with only electricmachine(s). In the example shown, engine system 100 includes engine 10and an electric machine 52. Electric machine 52 may be a motor or amotor/generator. Crankshaft 40 of engine 10 and electric machine 52 areconnected via a transmission 54 to vehicle drive wheels 55 when one ormore clutches 56 are engaged. In the depicted example, a first clutch 56is provided between crankshaft 40 and electric machine 52, and a secondclutch 56 is provided between electric machine 52 and transmission 54.Controller 12 may send a signal to an actuator of each clutch 56 toengage or disengage the clutch, so as to connect or disconnectcrankshaft 40 from electric machine 52 and the components connectedthereto, and/or connect or disconnect electric machine 52 fromtransmission 54 and the components connected thereto. Transmission 54may be a gearbox, a planetary gear system, or another type oftransmission. The powertrain may be configured in various mannersincluding as a parallel, a series, or a series-parallel hybrid vehicle.

Electric machine 52 receives electrical power from a traction battery 58to provide torque to vehicle wheels 55. Electric machine 52 may also beoperated as a generator to provide electrical power to charge battery58, for example during a braking operation.

As shown in FIG. 1, an engine system may include a CAC, such as CAC 80,arranged downstream of a compressor to cool boosted air beforecombustion at the cylinders. To reduce a likelihood of cooling the airbelow a dew point, leading to an undesirable decrease in MCT andcondensation in the CAC, intake passage, and intake manifold, the CACmay be adapted as a variable thermal capacity CAC (VTC-CAC) to adjustthe portion of air, and thereby the MCT, that is cooled. An exampleembodiment of a VTC-CAC 200 is depicted in FIG. 2 and includes anintegrated bypass 202 and cooling channels 204. A set of reference axes201 are provided for comparison between views shown in FIGS. 2-7C,indicating a “y” direction, “x” direction, and “z” direction. In someexamples, the “y” direction may align with a vertical axis, the “x”direction with a horizontal axis, and the “z” direction with a lateralaxis. However, other orientations have been contemplated. The view ofthe VTC-CAC is a cross-section taken along the plane formed by the “y”and “x” directions.

An outer shape of the VTC-CAC 200 may resemble a parallelogram withrounded corners, a greater length along the “y” direction than along the“x” direction, and without any planes of symmetry. In FIG. 2, theVTC-CAC 200 is shown aligned with the “y” direction so that the bypass202 and the cooling channels 204 are parallel with the “y” direction.The VTC-CAC 200 may have a first header tank 206 positioned at a top endof the VTC-CAC 200, with respect to the “y” direction. The first headertank 206 may be a first chamber into which boosted air may enter throughan inlet 208 that is proximal to the bypass 202 and may be coupled to anintake passage via a hose connected to the inlet 208. The first headertank 206 may have a top wall 210 that is angled with respect to the “x”direction so that a height 212 of the first header tank 206 at a first,cool side 214 of the VTC-CAC 200 is shorter than a height 216 at asecond, warm side 218 of the VTC-CAC 200.

The first header tank 206 is fluidly coupled to each of the coolingchannels 204, at first ends 205 of the cooling channels 204, and to thebypass 202. The cooling channels 204 may be a plurality of hollow tubesextending along the “y” direction from the first header tank 206 to asecond header tank 220, arranged at an opposite end of the VTC-CAC 200from the first header tank 206, and the cooling channels 204 fluidlycouple the first header tank 206 to the second header tank 220. Innervolumes of the cooling channels 204 are separated by tube walls 222. Thetube walls 222 may be configured with air fins attached to a frontsurface, e.g., a surface directly in contact with ram air. The coolingchannels 204 are adjacently arranged so that each cooling channel sharestwo tube walls 222, and attached air fins, with adjacent coolingchannels arranged on either side of the cooling channel except for theoutermost cooling channels 204, e.g. the cooling channel proximal to afirst side wall 224, also adapted with air fins, of the cool side 214and the cooling channel adjacent to the bypass 202, that only share onetube wall and air fin with an adjacent cooling channel. The side-by-sidecooling channels 204 extend from the first side wall 224 and air fin ofthe VTC-CAC 200 to an inner wall 226 of the bypass 202.

The bypass 202 may also extend from the first header tank 206 to thesecond header tank 220 and fluidly couple the first header tank 206 tothe second header tank 220. The bypass 202 may provide an alternateroute for air flow so that at least a portion of the air entering theVTC-CAC may be diverted from the cooling channels 204 and not cooledwhen the bypass 202 is open to air flow. The inner wall 226, as well asan outer wall 254, of the bypass 202 may be thicker than the tube walls222 to reduce heat transfer from the warmed air passing through thebypass to the air flowing through the cooling channels 204. The innerwall 226 and outer wall 254 of the bypass 202 may also be formed from aless thermally conductive material than the cooling channels 204 of theVTC-CAC to provide an insulating effect. A width of the bypass 202,defined along the “x” direction, may be greater than a width of one ofthe cooling channels 204 but significantly narrower than a cumulativewidth of all of the cooling channels 204 of the VTC-CAC 200.

The bypass 202 may be configured to maintain a warm temperature of aportion of a boosted air mass flowing through the VTC-CAC 200. Glowplugs 258 may be optionally arranged within the bypass 202 to augment atemperature of the bypassed air. For example, during cold engine starts,the glow plugs 258 may increase the MCT for faster engine warming. Asanother example, the glow plugs 258 may assist in raising the MCT to adesirable temperature when flowing warmed air through a fully openedbypass 202 does not increase the temperature sufficiently.

At an outlet end of the VTC-CAC 200, the second header tank 220 iscoupled to second ends 207 of the cooling channels 204 and to the bypass202. The second header tank 220 is similarly but oppositely configuredto the first header tank 206 with a bottom wall 228 that is angled sothat a height of the second header tank 220, defined along the “y”direction and proximal to the warm side 218 of the VTC-CAC 200, isshorter than a height of the second header tank 220 proximal to the coolside 214. An outlet 230 is included in the second header tank 220 thatmay also be coupled to the intake passage via a hose so that the VTC-CACis arranged as a section of the intake passage, e.g., in series with theintake passage. Air flowing through the cooling channels 204 and bypass202 may combine in the second header tank 220 and exit the VTC-CAC 200via the outlet 230. Cooling channels 204 to the left of the sliding gate234 that are blocked to air flow may include stagnant mixed air fromheader tank 220, resulting in a consistently lower temperature of theair within the blocked cooling channels 204 than the air entering fromthe inlet 208.

Returning to the first header tank 206 of the VTC-CAC 200, a dual-gatemechanism 232 may be disposed therein to control a division of air flowbetween the cooling channels 204 and the bypass 202. The dual-gatemechanism includes a sliding gate 234 that glides across the first ends205 of the cooling channels 204 along the “x” direction, a hinged gate236 adapted to pivot at a hinge 238, a threaded screw 240 extending fromthe cool side 214 to the warm side 218 of the VTC-CAC 200 in the firstheader tank 206, a stepper motor 242, a brake drum 244 housing a coilspring surrounded by a brake band (not shown in FIG. 2), and a solenoid246.

Movement of the sliding gate 234 and hinged gate 236 may be actuated bythe stepper motor 242 via coupling to the threaded screw 240 whererotational movement of the threaded screw 240 is translated into linearmovement of the sliding gate 234 along the “x” direction and pivoting ofthe hinged gate 236 in a counter-clockwise direction, with respect tothe view of the VTC-CAC 200 of FIG. 2. The movement of the sliding gate234 and hinged gate 236 may occur simultaneously, actuated by rotationof the threaded screw 240. Thus independent movement of either thesliding gate 234 or the hinged gate 236 may not be performed by the dualgate mechanism 232.

The stepper motor 242 may have a reduction gear fitted with a one-wayclutch (not shown in FIG. 2) to decrease a likelihood of the steppermotor freewheeling during rotation of the threaded screw when tension onthe brake band is released, described further below. The stepper motor242 may drive rotation of the threaded screw 240 in a first directionthat results in linear motion of the sliding gate 234 towards the warmside 218 of the VTC-CAC 200, hereafter referred to as a forwarddirection, and concurrent opening of the hinged gate 236 by pivoting inthe counter-clockwise direction at the fixed hinge 238. As the threadedscrew 240 rotates, the coil spring inside the brake drum 244 is wound upso that continued rotation of the threaded screw 240, moving the slidinggate in the forward direction while increasing the opening of the hingedgate 236, increases a tension of the coil spring. When the hinged gate236 reaches a fully opened position, pivoting about the hinge 238, thecoil spring may be under a maximum level of tension. The brake drum 244may maintain the current tension on the coil spring and hold a positionof the sliding gate 234 and hinged gate 236 at any time that the steppermotor 242 is stopped by engaging the brake band. The brake band maysurround the coil spring and resist a tendency for the coil spring torelieve tension. The interaction with the brake band may also overcomeany charge air pressure influence during events where charge airpressure may fluctuate and cause a pressure on the coil spring tofluctuate. The solenoid 246 may be activated while the stepper motor 242is driving rotation of the threaded screw 240 to allow the brake drum244 to rotate with the threaded screw 240.

By moving along the threaded screw 240 in the forward direction, thesliding gate 234 decreases a total volume of the VTC-CAC 200 throughwhich boosted air may flow and undergo heat transfer with the surfacesof the cooling channels 204. This may be achieved by a variable heightof the sliding gate 234, described further below in FIGS. 3-5, whichcuts off an inner volume of the first header tank 206, decreasing thevolume of the first header tank 206 that is fluidly coupled to theintake passage through the inlet 208 as the sliding gate 234 is drivenforwards by rotation of the threaded screw 240. The forward motion ofthe sliding gate 234 may also control the number of cooling channels 204that are available to cool boosted air. As the sliding gate 234 slidesalong the forward direction, the number of cooling channels 204 open toair flow decreases.

The decrease in volume of the VTC-CAC 200 available to cool boosted airresulting from the forward motion of the sliding gate 234 may be atleast partially offset by an opening of the hinged gate 236 to allow airto be diverted to the bypass 202. The simultaneous opening of the hingedgate 236 as the sliding gate 234 moves forward is also actuated by thestepper motor 242 and rotation of the threaded screw 240. Details of aconfiguration of the hinged gate 236 will be described further below, inFIGS. 4-6.

A distance that the hinged gate 236 may travel along the “x” direction,as the hinged gate 236 pivots, per full turn, e.g., 360 degree rotation,of the threaded screw 240 may be less than a distance travelled by thesliding gate 234 per full turn. The offset in distance travelled may beestablished by configuring the threaded screw 240 with different threadpitches. A first portion 248 of the threaded screw 240 may have a firstpitch size that differs from a second pitch size of a second portion 250of the threaded screw 240. The first portion 248 of the threaded screw240 may extend from the cool side 214 of the VTC-CAC 200 to a bypassopening 252 at a point where the hinged gate 236 may be positioned whenthe hinged gate 236 is in a fully closed position, e.g. parallel withthe “y” direction. The second portion 250 of the threaded screw 240 mayextend across a width of the bypass 202, defined along the “x”direction, from the inner wall 226 of the bypass 202 to the warm side218 of the VTC-CAC 200.

The offset in pitch size between the first pitch size of the firstportion 248 and the second pitch size of the second portion 250 of thethreaded screw 240 may be determined based on computational fluiddynamics (CFD) simulations. The first pitch size may be larger than thensecond pitch size according to a ratio, such as 10:1, that allows thesliding gate 234 to travel a larger distance relative to hinged gate 236along the “x” direction per full turn of the threaded screw 240.Furthermore, the offset in pitch sizes may be adapted to allow a fullopening of the hinged gate 236, which may be a maximum distance thehinged gate 236 may travel in the forward direction while pivoting thatis halted by contact of the hinged gate 236 with the outer wall 254 ofthe bypass 202, to coincide with a minimum number of cooling channels204 to be maintained open under any engine operating conditions ascontrolled by the position of the sliding gate 236. In other words,adjustment of the hinged gate 236 to the fully opened position, as shownin FIG. 7A, may stop the rotation of the threaded screw 240 andtherefore stop the movement of the sliding gate 234 in the forwarddirection, along the first ends 205 of the cooling channels 204. Thisterminal point of movement of the sliding gate 234 may be a maximumdistance the sliding gate 234 may travel in the forward direction and asa result, the cooling channels 204 with openings in front of thisposition may constantly be open to air flow.

The pitch sizes of the first and second portions 248, 250, of thethreaded screw 240 may be configured so that a minimum number of coolingchannels 204 are kept open when the hinged gate 236 is fully opened tomaintain a desirable distribution of air flow between the coolingchannels 204 and the bypass 202. The minimum number of cooling channels204 maintained open may also depend on a size and location of the inlet208. For example, if the inlet 208 were shifted proximal to a centralregion of the first header tank 206, the sliding gate 234 may slidetowards the cool side 218 of the VTC-CAC 200 to a maximum distance thataligns with a leftmost edge of the inlet 208. This results in a greaternumber of cooling channels 204 maintained open. This controlleddistribution may also conserve a pressure ratio across the inlet 208 andthe outlet 230 of the VTC-CAC 200, thereby decreasing a likelihood of achange in pressure of air passing through the VTC-CAC 200.

By driving the sliding gate 234 forward and the hinged gate 236 moreopen, more air is diverted to the bypass 202 and less air is cooledthrough the cooling channels 204. An increased routing of air throughthe bypass 202 may be desired when the manifold charge temperature (MCT)approaches a threshold such as a dew point. However, when the MCT risesand increased cooling of boosted air is desired, the sliding gate 234may be moved along the “x” direction from the warm side 218 to the coolside 214 of the VTC-CAC, in a reverse direction that is opposite of theforward direction, and the opening of the hinged gate 236 decreased bypivoting the hinged gate 236 in a clockwise direction.

Movement of the sliding gate 234 in the reverse direction and hingedgate 236 in the clockwise direction may be provided by deactivating thestepper motor 242 and disengaging the brake band holding the coil springin place within the brake drum 244 by actuating the solenoid 246. Themovement of the sliding gate 234 and hinged gate 236 in oppositedirections from those described above may also occur simultaneously, ascontrolled by rotation of the threaded screw 240, albeit in an oppositedirection. The solenoid releases the brake band and the tension on thecoil spring causes the coil spring to unwind, rotating the threadedscrew 240 in second direction opposite of the first rotational directionimposed by the stepper motor 242. The one-way clutch in the steppermotor reduction gear allows the rotation of the threaded screw 240 inthe second direction without freewheeling the stepper motor 242. Thesliding gate 234 and hinged gate 236 travel along the reverse andclockwise directions, respectively, until a desired proportioning of airbetween the cooling channels 204 and the bypass 202 is attained,determined based on a desired MCT. The deactivation of the solenoid 246re-engages the brake band with the coil spring when the sliding gate 234and hinged gate 236 are adjusted to the desired position and theposition of the sliding gate 234 and hinged gate 236 is maintained.

Furthermore, if the stepper motor 242 is degraded, the dual-gatemechanism 232 may be configured to actuate the solenoid in response tothe detected degradation, releasing the brake band. The hinged gate 236may be pivoted to the fully closed position, as shown in FIG. 7C, withthe sliding gate 234 positioned against an outer wall 256 of the coolside 214 of the VTC-CAC 200. This allows for a maximum number of coolingchannels 204 to be open to air flow, thus providing a maximum amount ofcooling to the boosted air and reducing a likelihood of an increase inMCT while a performance of the stepper motor 242 is degraded, hence adefault position of the VTC-CAC 200 when function of the stepper motor242 is compromised provides maximum charge air cooling.

In this way, the VTC-CAC may vary a cooling capacity of boosted airdelivered to the engine intake by dividing air flow between the coolingchannels and the bypass to achieve the desired MCT. The cooling effectof the VTC-CAC is controlled by a single mechanism that adjusts theinner volume of the VTC-CAC that provides cooling of a first portion ofthe air as well as the opening of the bypass that maintains a highertemperature of a second, bypassed portion of the air. Mixing of the airwithin the second header tank at the outlet end of the VTC-CAC generatesa temperature that falls between the individual temperatures of thefirst and second portions. By controlling the MCT via variable cooling,an engine's combustion efficiency may be increased while emissions ofcarbon monoxide and hydrocarbons as well as condensation within theengine intake are reduced.

It will be appreciated that while the embodiment of the VTC-CAC andcomponents of the VTC-CAC shown in FIGS. 2-7C are depicted with certaingeometries and amounts of components, other shapes, sizes, andquantities have been contemplated. For example, an outer shape of theVTC-CAC may resemble a rectangle or a square instead of a parallelogram,the alignment of the cooling channels and bypass within the VTC-CAC mayvary relative to the outer geometry, the number cooling channels may bemore or less than those shown, the width of the bypass may be wider ornarrower than the bypass shown, etc. Thus, it will be appreciated thatsuch deviations from the example embodiments shown should not departfrom the scope of the present disclosure.

The VTC-CAC 200 is imparted with a variable thermal capacity byadjusting positions of the sliding gate 234 and hinged gate 236 so thatthe sliding gate 234 blocks air flow through a desired number of coolingchannels 204. Aspects of the sliding gate 234 will be discussed withreference to FIGS. 3-5 regarding how the sliding gate 234 seals off aportion of the cooling channels 204. Elements introduced in FIG. 2 aresimilarly numbered.

The VTC-CAC 200 is shown in FIG. 3 from a direction that provides afront view of the sliding gate 234, e.g. along the “z” direction,viewing the sliding gate 234 along the “x” direction from the warm side218 to the cool side 214 of the VTC-CAC 200. While outer surfaces of thestepper motor 242, the bypass 202 and the inlet 208 in the first headertank 206 are shown, a cut-away view of an upper portion of the slidinggate 234, housed within the first header tank 206, is shown in box 300.A top edge 306 of the sliding gate 234 may be in contact with an innerface of the top wall 210 across an entire depth of the inner face of thetop wall 210, the depth defined along the “z” direction. Sides 308 ofthe sliding gate 234, the sides being coaxial with the “z” direction,may be in contact with inner side surfaces of the first header tank 206along an entire height of the sliding gate 234, with the height definedalong the “y” axis. The top wall 210 of the first header tank 206 may becast with rails 302 protruding from sides of the first header tank 206and extending along a width of the header tank, defined along the “x”direction, to accommodate and enclose high temperature bearings 304 ofthe sliding gate 234.

The high temperature bearings 304 may be configured to allow movement ofthe sliding gate 234 along the “x” direction while maintaining contactbetween the top edge 306 of the sliding gate 234 and the inner surfaceof the top wall 210 of the first header tank 206 via nested sections,described further below. The high temperature bearings 304 may beconnected proximal to the top edge 306 of the sliding gate 234 andarranged along the sides 308 of the sliding gate 234. The hightemperature bearings 302 may protrude from the sides 308 of the slidinggate 234 to be positioned and fixed with the rails 304. The sliding gate234 may thus slide unhindered along the “x” direction in the firstheader tank 206 by rolling of the high temperature bearings 304 withinthe rails 302 of the first header tank 206. As the threaded screw 240rotates, the sliding gate 234 moves along the threaded screw 240 byinteraction between a first threaded insert 404 disposed in the slidinggate 234, shown in FIGS. 4-5 and described below, and the threaded screw240. The high temperature bearings 304 allow an upper portion of thesliding gate 234 to move along the “x” direction while maintaining avertical, e.g., parallel with the “y” direction, alignment of thesliding gate 234. The contact between the top edge 306 and the sides 308of the sliding gate 234 with the inner face of the top wall 210 andinner side surfaces of first header tank 206 seals a portion of theinner volume of the first header tank 206 between a distance, along the“x” direction, from the sliding gate 234 to the outer wall 254 of thebypass 202.

The high temperature bearings 304 may be located at a warmest region ofthe VTC-CAC 200, within a top region of the first header tank 206 wherewarmed boosted air first enters the VTC-CAC 200. In one example, thehigh temperature bearings 304 may be formed from a material with a highheat tolerance such as silicon nitride, zirconia, or silicon carbidethat allow movement of the high temperature bearings 304 withoutlubrication. The sliding gate 234 may also comprise a second set ofbearings that may also be configured to roll within a second set ofrails arranged proximal to a bottom edge of the sliding gate 234 andcast into the sides of the first header tank 206, extending along thewidth (e.g., along the “x” direction) of the VTC-CAC 200. The second setof bearings are shown in the perspective views 400 and 500 of theVTC-CAC 200 depicted in FIGS. 4 and 5.

The perspective views 400 and 500 of FIGS. 4 and 5 show the VTC-CAC 200with the dual-gate mechanism 232 arranged above a CAC core 402 thatincludes the cooling channels 204 and tube walls 222 and attached airfins. The first header tank 206 is omitted from both FIGS. 4 and 5 andthe bypass 202 is omitted from FIG. 4. The sliding gate 234 of thedual-gate mechanism 232 may have a rectangular outer shape with a secondset of bearings 406 arranged along the sides 308 of the sliding gate 234and proximal to a bottom edge 408 of the sliding gate 234, the bottomedge 408 being parallel with the top edge 306. The sliding gate 234 maybe formed from a rigid material with a high heat tolerance and marginalthermal expansion, such as aluminum, carbon graphite, bronze, orcomposite. It will be appreciated, however, that the sliding gate 234 isa non-limiting example and other examples of the sliding gate maycomprise outer shapes of different sizes and geometries, depending on aninner shape of the first header tank, or formed from other rigidmaterials.

The second set of bearings 406 may function similarly to the hightemperature bearings 304, allowing the bottom edge 408 of the slidinggate 234 to slide unhindered along a width of the first header tank 206when compelled by rotation of the threaded screw 240 while maintainingthe upright position of the sliding gate 234. The second set of bearings406 may be enclosed within rails, similar to the rails 302 of FIG. 3,disposed in the sides of the first header tank 206 and may be formed ofa same material as the high temperature bearings 304.

The bottom edge 408 of the sliding gate 234 may be in contact along anentire depth, defined along the “z” direction, with an upper surface 410of the CAC core 402 in which first ends 205 of the cooling channels 204are disposed. One or more rows of the cooling channels 204, the rowsalso defined along the “z” direction, may thereby be blocked by thesliding gate 234. For example, returning to FIG. 2, the sliding gate 234may have a thickness, defined along the “x” direction” that is at leastequal to diameters of the cooling channels 204 (measured along the “x”direction) and therefore may fully block one row of the cooling channels204 when positioned directly above the row. In other words, if thesliding gate 234 were arranged directly over cooling channel 204 a ofFIG. 2 (representing one row of the cooling channels 204), the coolingchannels 204 in front of sliding gate 234, including all the coolingchannels 204 from the cooling channel proximal to the bypass 202 up tocooling channel 204 b (also representing one row of the cooling channels204), are not blocked. Therefore cooling channel 204 b and all thecooling channels 204 in front of cooling channel 240b are open to airflow and cooling channel 204 a and all the cooling channels 204 behindcooling channel 204 a, and including cooling channel 204 a, are blockedto air flow. In another example, the sliding gate 234 may be positionedso that the thickness of the sliding gate 234 extends partially across adiameter of cooling channel 204 a as well as partially across a diameterof cooling channel 204 b. In this position, cooling channel 204 b andall the cooling channels 204 in front are again open to air flow,although flow through cooling channel 204 b may experience restriction,while cooling channel 204 a and all the cooling channels behind coolingchannel 204 a are blocked.

The sliding gate 234 may maintain a sealing interaction with innersurfaces of the first header tank 206, in spite of the variable heightof the first header tank 206, as shown in FIG. 2, by comprising sectionsthat nest within one another. In FIGS. 4 and 5, the sliding gate 234includes a first section 412 that is a largest section of the slidinggate 234 in which the first threaded insert 404 is centrally arranged, asecond section 414 above the first section 412, and a third section 416above the second section 414 that includes the top edge 306 of thesliding gate 234 and the high temperature bearings 304. A size(including a thickness, defined along the “x” direction, and a depth,defined along the “z” direction) of the second section 414 may besmaller than a size of the first section 412 so that the second section414 may fit within and be at least partially enclosed by the firstsection 412. In other words, the second section 414 may be adapted tonest within the first section 412 and slide up and down, along the “y”direction, relative to first section 412. The upward sliding of allnested sections may be halted at an end of their travel by lock pins oneither side of each section, along the “z” direction (not shown), whichallows the uppermost third section 416 to drive the vertical motion ofthe slideable sections below (e.g., the second section 414). Astructural integrity of the assembly is thus maintained when the hightemperature bearings 304 slide in their perspective rails 302 to conformto the cross-sectional area of the first header tank 206. The downwardsliding of the second section 414, however, may be halted by contactwith a flat-machined surface 411 in the first section 412 of the slidinggate 234. The third section 416 may be similarly configured to nestwithin the second section 414 and slide up and down relative to thesecond section 414, with the downward motion halted by contact with aflat-machined surface 413 of the second section 414 (as shown in FIG.5).

In this way, a height 418 of the sliding gate 234 may be adjustedaccording to changes in height of the first header tank 206 as thesliding gate 234 moves along the forward and reverse directions. Contactbetween the top edge 306 of the sliding gate 234 and the inner face ofthe top wall 210 of the first header tank 206 is maintained byconfinement of the high temperature bearings 304 within the rails 302 ofthe first header tank 206, as shown in FIG. 2. As the height of thefirst header tank 206 changes along the width of the first header tank206, the third section 416 may slide in and out of the second section414, which may slide in and out of the first section 412 of the slidinggate 234, providing expansion and contraction of the height 418. Bymatching the height 418 of the sliding gate 234 with the height of thefirst header tank 206, the sliding gate 234 may seal and block an innervolume of the VTC-CAC 200, defined by a volume of the first header tank206 that is behind the sliding gate 234 and by a number of the coolingchannels 204 that are behind the foremost cooling channel blocked by thesliding gate 234, from air flow, simultaneously controlling the numberof cooling channels 204 available to cool boosted air. It will beappreciated that while three sections of the sliding gate 234 are shownin FIGS. 4 and 5, different quantities of nesting sections have beencontemplated, such as two sections, four sections, or five sections.Furthermore in embodiments of the VTC-CAC 200 where the first headertank has a uniform height, the sliding gate may include a single sectionthat does not vary in height.

The first section 412 of the sliding gate 234 may have a centralaperture, extending through the thickness of the first section in whichthe first threaded insert 404 is disposed. The first threaded insert 404may be annular with a threaded inner surface configured to mate with thepitch size of the first portion 248 of the threaded screw 240. The firstthreaded insert 404 may be fixed to the first section 412 so that thefirst threaded insert 404 may not rotate. When the threaded screw 240 isturned by the stepper motor 242, the threaded screw 240 is held in placewhile rotating, e.g., the threaded screw 240 does not movetranslationally. Instead, the mating of the threading in the innersurface of the first threaded insert 404 with the thread pitch of thefirst portion 248 of the threaded screw 240 converts the rotationalmovement of the threaded screw 240 into translational movement of thesliding gate 234 in the forward direction.

The rotation of the threaded screw 240 may also drive movement of thehinged gate 236. The hinged gate 236 may have a rectangular shape, asshown in FIGS. 2 and 4, as well as a perspective view 600 of FIG. 6,showing the arrangement of the hinged gate 236 in the VTC-CAC 200 withthe bypass 202 omitted. The hinged gate 236 may have a depth, definedalong the “z” direction, equal to the depth of the first header tank 206so that side edges 504 of the hinged gate 236 are in contact with sidewalls 502 of the bypass 202. In one example, a height of the hinged gate236, defined along the “y” direction, may be slightly greater than aheight of the first header tank 206 at the point where the hinge 238 ofthe hinged gate 236 is attached to the side walls 502 of the bypass 202.In other examples, however, the hinged gate 236 may have a differentshape that corresponds to an inner geometry of the bypass 202. Unlikethe sliding gate 234, the hinged gate 236 may not maintain an alignmentthat is parallel with the “y” direction as the hinged gate moves. Thehinged gate 236 may pivot in the counterclockwise direction at the hinge238 to increase the bypass opening 252 while the sliding gate 234 ismoving along the forward direction as guided by the threaded screw 240.

An angle of the hinged gate 236 with respect to the “y” direction mayincrease as the bypass opening 252 is widened. The angle may varybetween 0 degrees when the hinged gate 236 is in the fully closedposition up to 30 degrees, in one example, when the hinged gate 236 isin the fully open position and a bottom edge 420 of the hinged gate 236is in contact with the outer wall 254 of the bypass 202. In otherexamples, however, the range of angles through which the hinged gate 236may pivot may vary according to a width of the bypass, defined along the“x” direction, a height of the hinged gate 236, or a positioning of asecond threaded insert 422 in the hinged gate 236.

The second threaded insert 422 may be similarly configured as the firstthreaded insert 404, having an annular shape and comprising a threadedinner surface that mates with the pitch size of the second portion 250of the threaded screw 240. The second threaded insert 422 may be fixedso that it may not rotate within a spherical bearing 424 thatcircumferentially surrounds the second threaded insert 422, as shown inFIGS. 4-6. The spherical bearing 424 may be modified such that an innersphere of the spherical bearing 424 that houses the second threadedinsert 422 is restricted from rotating in the same direction of thethreaded screw 240 through the insertion of a small pin in the innersphere that floats in a groove in an outer part of the spherical bearing424. The second threaded insert 422 and the spherical bearing 424 may bedisposed in an aperture extending through a thickness, defined along the“x” direction, of the hinged gate 236. As the hinged gate 236 is pivotedmore open and the angle of the hinged gate 236 increases with respect tothe “y” axis, an angle between the plane of the hinged gate 236 and thethreaded screw 240 may decrease. A position of the second threadedinsert 422 is fixed within the spherical bearing 424, therefore therotation of the threaded screw swivels the spherical bearing 424, asindicated by arrow 602, which in turn accommodates the change in anglebetween the hinged gate 236 and the threaded screw 240 without imposingstress on the hinged gate 236 or threaded screw 240. The hinge 238 ishoused in bypass 202 within a slightly oversized groove to allow adegree of freedom in the “y” direction when hinged gate 236 pivots fromthe fully closed to the fully opened position.

The spherical bearing 424 and second threaded insert 422 may becentrally disposed in the hinged gate 236. However, in other examplesthe spherical bearing 424 and second threaded insert 422, as well as thefirst threaded insert 404, may be offset from a center of the hingedgate 236 and sliding gate 234, respectively. The threaded screw 240 maybe positioned higher, lower or biased to one side and the apertures inthe hinged gate 236 and sliding gate 234 may be accordingly adjusted.Furthermore, the first and second threaded inserts 404, 422, andspherical bearing 424 may be formed from a heat tolerant material suchas stainless steel.

A cut-out 426 may be disposed in a surface of the hinged gate 236 facingthe cool side 214 of the VTC-CAC 200 and proximal to the bottom edge 420of the hinged gate 236. The thickness of the hinged gate 236 may bereduced at the cut-out 426 to allow the hinged gate 236 to form asealing engagement with the CAC core 402 when the hinged gate 236 is inthe fully closed position. As shown in FIG. 7C, the cut-out 426 may bein face-sharing contact with the inner wall 226 of the bypass 202 in thefully closed position of the hinged gate 236. The reduced thickness ofthe cut-out 426 allows the hinged gate 236 to be parallel with the “y”direction when closed and blocks air from flowing into the bypass 202under the bottom edge 420 of the hinged gate 236.

The hinged gate 236 may be further sealed by a sealing strip 428 arrangealong a top edge 430 of the hinged gate 236 and extending across thedepth of the hinged gate 236. The sealing strip 428 may extend along the“y” direction from a top edge 430 of the hinged gate 236 to an innerface of the outer wall 254 of the bypass 202. The sealing strip 428 maybe formed from a flexible, heat resistant material such as rubber orsilicone, the flexibility of the sealing strip 428 allowing it tomaintain a sealing contact between the top edge 430 of the hinged gate236 and the inner face of the outer wall 254 of the bypass 202regardless of the angle of the hinged gate with respect to the “y”direction. In this way, air in the first header tank 206 may enter thebypass 202 by flowing under the bottom edge 420 of the hinged gate 236and not around the side edges 504 or over the top edge 430 of the hingedgate 236.

The concerted positioning of the sliding gate 234 and hinged gate 236when the threaded screw 240 is rotated by the stepper motor 242 toadjust flow through the cooling channels 204 and the bypass 202 of theVTC-CAC 200 or when stepper motor 242 is deactivated and the brake bandreleased to allow movement in the reverse direction is represented bypositions shown in FIGS. 7A-C. Cross-sections of the VTC-CAC 200, takenalong plane formed by the “y” and “x” directions, are depicted. Thesliding gate 234 may include, along the first section 412, secondsection 414, and third section 416, a fourth section 710 positionedabove the third section 416 and configured to nest with the thirdsection 416. The high temperature bearings 304 may be attached to thefourth section 710 instead of the third section 416 in FIGS. 7A-C.

In a first position 700 of FIG. 7A, the sliding gate 234 may be at afirst mid-point 702 of the first portion 248 of the threaded screw 240,between the inner wall 226 of the bypass 202 and the outer wall 256 ofthe cool side 214 of the VTC-CAC 200. The hinged gate 236 may be in thefully open position, e.g., the bypass opening 252 is at a maximum, withthe bottom edge 420 in contact with the outer wall 254 of the bypass202. The thread pitches of the first and second portions 248, 250 of thethreaded screw 240 may be configured so that the fully open position ofthe hinged gate 236 may coincide with the forward movement of thesliding gate 236 terminating at the first position 700 that maintains aminimum number of cooling channels 204 open to air flow. This mayrepresent a constant minimum amount of cooling provided by the VTC-CAC200 in addition to a maximum amount of air that may bypass the coolingchannels 204. In one example, the minimum number of cooling channels tobe maintained open may be set based on a calculated minimum amount ofwarming imposed by compression of intake air and difference between theminimum amount of warming and a desired MCT. In the example shown, lessthan half but greater than one quarter of the cooling channels may bemaintained open when the dual-gate mechanism is in the first (e.g.,fully open) position. However, in other examples, the minimum number ofopen cooling channels 204 may be determined by a physical constraint. Asone example, a maximum distance the sliding gate may travel in theforward direction is set by alignment with the edge of the inlet 208proximal to the warm side 214 of the VTC-CAC 200.

A second position 720 of the dual-gate mechanism 232 of the VTC-CAC isshown in FIG. 7B. The second position 720 includes a partially openposition, e.g., between the fully open and the fully closed positions,of the hinged gate 236. The sliding gate 234 may be at a secondmid-point 704 along the first portion 248 of the threaded screw 240. Thesecond mid-point 704 may be closer to the cool side 214 of the VTC-CACthan the first mid-point 702 of FIG. 7A and may correspond to a positionof the hinged gate 236 that is less open than the fully open position ofFIG. 7A. The hinged gate 234 forms a larger angle relative to thethreaded screw 240 compared to the angle between the hinged gate 234 andthe threaded screw 240 in the first position 700 and the sphericalbearing 424 in the hinged gate 234 may rotate to accommodate the changein angle. In the second position 720 of FIG. 7B, a greater number ofcooling channels 204 are open to air flow than in the first position 700of FIG. 7A and less air may be diverted through the bypass 202 due to anarrower bypass opening 252 in the second position 720.

Actuation of the dual-gate mechanism 232 from the first position 700 tothe second position 720 may occur when increased cooling of the intakeair is requested, such as during events where the MCT is detected toincrease (e.g., above a threshold temperature). Greater cooling of theboosted air may be desirable to lower the MCT temperature and, inresponse to the rise in MCT, the stepper motor 242 may be deactivatedand the solenoid 246 actuated to release the brake band in the brakedrum 244 that maintains tension on the coil spring. The release oftension on the coil spring allows the threaded screw 240 to rotate inthe second direction, driving the sliding gate 234 along the reverse andhinged gate 236 along the clockwise direction until the number of opencooling channels 204 and the bypass opening 252 reach a position that isdetermined to produce a portioning of warm and cool air to produce thedesired decrease in MCT.

Conversely, actuation of the dual-gate mechanism 232 from the secondposition 720 to the first position 700 may occur when decreased coolingof the intake air is requested, such as when the MCT is detected todecrease (e.g., to below a threshold). To increase the MCT, the steppermotor 242 may be activated to turn the threaded screw in the firstdirection to reduce the number of cooling channels 204 open to air flowand widen the bypass opening 252 to divert more air to the bypass 202.The mixture of air in the second header tank 220 may comprise a greaterportion of warm air in the first position 700 than obtained from thesecond position 720, thus delivering a warmer mixture of boosted air andraising the MCT.

It will be appreciated that the second position 720 of FIG. 7B is anon-limiting example of a position in between the fully open and fullyclosed positions of the hinged gate 236 and the corresponding positionof the sliding gate 234. In other examples, the hinged gate 236 andsliding gate 234 may be adjusted to any position in between the fullyopen and fully closed positions of the hinged gate 236 and correspondingpositions of the sliding gate 234 to vary air flow between the coolingchannels 204 and bypass 202. Thus a continuum of adjustments to the MCTmay be achieved.

The fully closed position of the hinged gate 236 is depicted in a thirdposition 740 of the dual-gate mechanism 232 in FIG. 7C. The hinged gate236 may be adjusted so that the cut-out 426 of the hinged gate 236 is inface-sharing contact with a surface of the inner wall 226 of the bypass202 that is facing the warm side 218 of the VTC-CAC 200. The fullyclosed position of the hinged gate 236 may correspond to a position tothe sliding gate 234 where the sliding gate 234 is shifted to a maximumextent toward the cool side 214 of the VTC-CAC 200. The sliding gate maybe in contact with the outer wall 256 of the cool side 214 and all thecooling channels 204 may be open to air flow. This position may allow agreatest level of cooling of boosted air provided by the VTC-CAC 200 byclosing the bypass 202 and directing all the intake air through thecooling channels 204.

The adjustment of the dual-gate mechanism 232 to the third position 740of FIG. 7C may occur when the MCT is determined to be high enough that alikelihood of engine knock is increased. The stepper motor 242 isdeactivated or maintained deactivated, the solenoid 246 is actuated torelease the brake band, and the release of tension on the coil springdrives the rotation of the threaded screw 240 in the second direction.The sliding gate 234 travels along the reverse direction and the hingedgate 236 pivots in the clockwise direction until movement is terminatedby contact between the sliding gate 234 and the outer wall 256 of thecool side 214 of the VTC-CAC 200 and between the cut-out 426 of thehinged gate 236 and the surface of the inner wall 226 of the bypass 202.All the air delivered through the intake passage may be cooled by thecooling channels 204 of the VTC-CAC 200, resulting in a decrease in theMCT.

Alternatively, the dual-gate mechanism 232 may be adjusted to the thirdposition 740 if the stepper motor 242 is detected to malfunction. Whileover-cooling of the intake air may reduce combustion efficiency,degradation of engine components is more significant during overheatingof the engine than during over-cooling. Thus, by setting the fullyclosed position of the hinged gate 236 as a default position when thestepper motor 242 is unable to drive the sliding gate 234 and hingedgate 236 along the forward direction, an increase in MCT iscircumvented.

FIGS. 1-7C show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example. As yet another example, shapes of theelements depicted within the figures may be referred to as having thoseshapes (e.g., such as being circular, straight, planar, curved, rounded,chamfered, angled, or the like). Further, elements shown intersectingone another may be referred to as intersecting elements or intersectingone another, in at least one example. Further still, an element shownwithin another element or shown outside of another element may bereferred as such, in one example.

The manifold charge temperature (MCT) may be adjusted to a temperaturethat increases engine efficiency, reduces a likelihood of engine knockand formation of condensation in the intake region of the engine, anddecreases emissions of carbon monoxide and hydrocarbons. Regulation ofthe MCT may be achieved by a variable thermal capacity charge air cooler(VTC-CAC), such as the VTC-CAC 200 of FIGS. 2-7C, configured with anintegrated bypass and a dual-gate mechanism, e.g., the dual-gatemechanism 232 of FIGS. 2-7C. A method 800 for operating an engine systemcomprising the VTC-CAC adapted with the integrated bypass and dual-gatemechanism is provided in FIG. 8. Instructions for carrying out method800 and the rest of the methods included herein may be executed by acontroller, such as controller 12 of FIG. 1, based on instructionsstored on a memory of the controller and in conjunction with signalsreceived from sensors of the engine system, such as the sensorsdescribed above with reference to FIG. 1. The controller may employengine actuators of the engine system to adjust engine operation,according to the methods described below.

At 802, the method includes estimating and/or measuring the operatingconditions of the engine. These may include, for example, an enginecoolant temperature (ECT) measured by a temperature sensor such astemperature sensor 112 of FIG. 1 and the manifold charge temperature(MCT) detected by a temperature sensor in an intake manifold of theengine, such as temperature sensor 124 of FIG. 1. A pressure of boostedair may be measured by a pressure sensor, such as pressure sensor 126 ofFIG. 1 and compared to a manifold absolute pressure (MAP), measured byanother pressure sensor, such as manifold pressure sensor 122 of FIG. 1,to monitor changes in pressure across the VTC-CAC. A position of thedual-gate mechanism may be detected by sensors arranged the hinged gateof the mechanism or by an encoder installed on the threaded screw.Alternatively, the encoder may be positioned at the stepper motor todetect positions of the sliding gate and hinged gate at any instant.Other operating conditions determined may include a mass airflow intothe intake system, ambient temperature, ambient humidity, and barometricpressure.

The method may determine at 804 whether the measured MCT falls below afirst temperature threshold. In one example, the first temperaturethreshold may be a temperature at which a likelihood of engine knock andrelease of NOx emissions is increased when the MCT rises above thesecond temperature threshold. The first temperature threshold maytherefore be an upper boundary of a temperature range through whichengine operation is at a desirable combustion efficiency, fuelefficiency, and performance. This may be a value programmed into thecontroller's memory and may depend on specific characteristics of theengine.

If the MCT is measured below the first temperature threshold, the methodcontinues to 806 where the stepper motor is deactivated, e.g., turnedoff, or maintained deactivated if the stepper motor is already off. At808, the solenoid, coupled to the stepper motor, is activated to releasethe brake band, thereby allowing tension on a coil spring to bealleviated. The release of tension on the coil spring causes a threadedscrew of the dual-gate mechanism to rotate in a direction that drives alinear movement of a sliding gate in a reverse direction, e.g., from awarm side to a cool side of the VTC-CAC. The direction of rotation ofthe threaded screw that drives the movement of the sliding gate in thereverse direction is the second direction described above with respectto FIGS. 2-7C. Concurrently, the rotation of the threaded screw alsocompels a closing of a hinged gate to block an opening to the integratedbypass. When the dual-gate mechanism reaches a fully closed position ofthe hinged gate, the sliding gate also reaches a maximum distance thatthe sliding gate may travel across the VTC-CAC, towards the cool side,and the solenoid is deactivated at 810. At 812, intake air is flowedthrough all the cooling channels of the VTC-CAC and no intake air flowsthrough the integrated bypass. The method may return to 804 to againmeasure the MCT and compare the temperature to the first temperaturethreshold.

If the MCT is determined to be below the first temperature threshold,the method proceeds to 814. At 814, the MCT is compared to a secondtemperature threshold. The second temperature threshold may be aninferred temperature at or below which combustion efficiency, based onthe measured ambient temperature, may be reduced, or based on ambientconditions such as humidity and barometric pressure, as described above.For example, when the MCT is lower than the second temperaturethreshold, a likelihood of condensation forming within the intakeregion, e.g., in cooling channels of the VTC-CAC, is increased. Inanother example, the second temperature threshold may be a temperaturebelow which release of combustion products such as carbon monoxide andhydrocarbons to the atmosphere is increased.

If the MCT is not above the second temperature threshold, the methodcontinues to 816 to activate the solenoid to release the brake band. At818, the stepper motor is activated to rotate the threaded screw in thefirst direction (e.g., described above with respect to FIGS. 2-7C).Rotation of the threaded screw in this direction drives a forward, e.g.,from the cool side to the warm side of the VTC-CAC, movement of thesliding gate as well as an opening of the hinged gate to increase intakeair flow through the integrated bypass. The linear motion of the slidinggate and pivoting of the hinged gate continue until the pivoting of thehinged gate is stopped by contact between the hinged gate and an outerwall of the bypass. At this position, a fraction, representing a minimumamount of cooling provided by the VTC-CAC, of the cooling channelsremain open, such as 25%, or another value determined based on ageometry of a header tank enclosing the dual-gate mechanism and analysisby CFD. The stepper motor and the solenoid are deactivated at 820 withthe hinged gate in a fully open position. Intake air is flowed throughthe reduced number of open cooling channels and through the fully openedbypass at 822. The method may return to 814 to again measure the MCT andcompare the temperature to the second temperature threshold.

If the MCT is determined to be higher than the second temperaturethreshold, the method continues to 824 to estimate a target position ofthe dual-gate mechanism based on the current engine conditions. Forexample, the controller may calculate a MCT that provides a maximumcombustion efficiency and engine power output based on a current enginespeed and load, the calculated MCT falling within a temperature rangebetween the first and second temperature thresholds. The controller mayinfer a position of the dual-gate mechanism that adjusts the current MCTtoward the target MCT. In another example, the controller may monitor anamount of condensate forming within the cooling channels of the VTC-CAC.The amount of condensation may be determined from an inferredcondensation formation value, calculated based on air flow velocity fromMAF measurement and/or from a difference between the dew point of theintake air and either a temperature of the VTC-CAC or the MCT. In stillfurther examples, the target position of the dual-gate mechanism may bebased on engine speed and engine load (e.g., the controller may access alook-up table that plots target position of the dual-gate mechanism as afunction of engine speed and engine load), mass air flow, boostpressure, EGR amount, and/or other operating parameters.

At 826, the position of the dual-gate mechanism may be adjusted based onan offset from the estimated target position. If the current MCT islower than a target or desired MCT, the stepper motor and solenoid maybe activated to increase the opening of the integrated bypass anddecrease the number of open cooling channels until the target positionis reached. Thus, as indicated at 828, adjusting the position of thedual-gate mechanism may include activating the stepper motor andsolenoid until the dual-gate mechanism reaches the target position. Onthe other hand, if the current MCT is higher than the target or desiredMCT, the stepper motor is deactivated and the solenoid activated todecrease the integrated bypass opening and increase the number of opencooling channels until the target position is reached. Thus, asindicated at 830, adjusting the position of the dual-gate mechanism mayinclude deactivating the stepper motor and activating the solenoid untilthe dual-gate mechanism reaches the target position.

Alternatively, if the condensation in the VTC-CAC is determined toincrease above a threshold amount, such as an amount that may causemisfire at the cylinders if purged to the intake manifold, the dual-gatemechanism may be adjusted so that the hinged gate is fully open and aminimum number of cooling channels are open to intake air flow,regardless of the position of the dual-gate mechanism relative to thetarget position. In this way, a likelihood of introduction of excessiveamounts of condensate to the combustion chambers is decreased. Thedual-gate mechanism may be maintained in this position until furthersteps to remove the condensate are performed, such as purging to acollection vessel, etc.

At 832, the method includes flowing intake air through the subset ofcooling channels that are not blocked by the sliding gate and throughthe bypass, with the dual-gate mechanism adjusted to the targetposition. The method may return to 814 to again measure the MCT andcompare the temperature to the second temperature threshold.

In this way, a MCT may be adjusted by adapting an engine system with avariable thermal capacity charge air cooler (VTC-CAC). The VTC-CAC mayinclude an integrated bypass that diverts air from cooling channels ofthe VTC-CAC and a dual-gate mechanism that adjusts a division of airbetween the cooling channels and the bypass. By configuring the VTC-CACwith the dual-gate mechanism that is controlled by a single actuatingdevice comprising a stepper motor coupled to a solenoid, the MCT may becontrolled without increasing a size or complexity of the charge aircooler. A synchronized adjustment of flow between the cooling channelsand the bypass circumvents changes in pressure across an inlet and anoutlet of the VTC-CAC as well as changes in air flow rate through theVTC-CAC. Furthermore, by configuring the positioning of the dual-gatemechanism to depend solely on the measured MCT, no additional controlsare introduced into the system. The MCT may be maintained within adesirable range that enhances combustion efficiency while decreasing alikelihood of engine knock, condensation, and emission of carbonmonoxide and hydrocarbons. The technical effect of adjusting MCT via theVTC-CAC is that a performance and power output of the engine is improvedwhile occurrences of both engine knock due to high MCT and misfire dueto condensation are decreased.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory and may be carried outby the control system including the controller in combination with thevarious sensors, actuators, and other engine hardware. The specificroutines described herein may represent one or more of any number ofprocessing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various actions,operations, and/or functions illustrated may be performed in thesequence illustrated, in parallel, or in some cases omitted. Likewise,the order of processing is not necessarily required to achieve thefeatures and advantages of the example embodiments described herein, butis provided for ease of illustration and description. One or more of theillustrated actions, operations and/or functions may be repeatedlyperformed depending on the particular strategy being used. Further, thedescribed actions, operations and/or functions may graphically representcode to be programmed into non-transitory memory of the computerreadable storage medium in the engine control system, where thedescribed actions are carried out by executing the instructions in asystem including the various engine hardware components in combinationwith the electronic controller.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,I-4, I-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and non-obvious combinationsand sub-combinations of the various systems and configurations, andother features, functions, and/or properties disclosed herein.

As one embodiment, a cooling system of an engine includes an intakepassage configured to deliver boosted air to an intake manifold of theengine, a charge air cooler adapted to received boosted air from theintake passage via an inlet and return boosted air to the intake passagevia an outlet, the charge air cooler comprising an integrated bypass, aplurality of cooling channels, and a dual-gate mechanism including afirst gate dividing the integrated bypass from the plurality of coolingchannels and a second gate dividing the plurality of cooling channelsinto open channels and blocked channels, the blocked channelsfluidically blocked from receiving intake air. In a first example of thesystem, the inlet is arranged in a first header tank and the outlet isarranged in a second header tank that is positioned at an opposite endfrom the first header tank of the charge air cooler, and wherein theplurality of cooling channels and the integrated bypass each fluidlycouple the first header tank to the second header tank. A second exampleof the system optionally includes the first example and further includeswherein the dual-gate mechanism is positioned in the first header tank,and wherein the engine is coupled in a hybrid-electric vehiclepowertrain. A third example of the system optionally includes one ormore of the first and second examples and further includes a steppermotor configured to actuate the dual-gate mechanism and drivesimultaneous movement of the first gate and the second gate, the steppermotor arranged external to the first header tank. A fourth example ofthe system optionally includes one or more of the first through thirdexamples, and further includes, wherein the second gate extends along anentirety of the first header tank in a first direction from theplurality of cooling channels to a top of the first header tank and in asecond direction from a first side of the first header tank to a secondside of the first header tank, and the open channels include eachcooling channel on a hot side of the first header tank and the blockedchannels include each cooling channel on a cool side of the first headertank, a boundary between the hot side of the first header tank and thecool side of the first header tank defined by the second gate, the inletpositioned on the hot side of the first header tank, and wherein thesecond gate is configured to move laterally in the first header tank tosimultaneously adjust a number of cooling channels comprising the openchannels and a number cooling channels comprising the blocked channels.

In another embodiment, a variable thermal capacity charge air cooler(VTC-CAC) includes an integrated bypass, a plurality of coolingchannels, arranged parallel with and adjacent to the bypass, a dual-gatemechanism configured with a sliding gate positioned in a first headertank that fluidically couples openings of the cooling channels to aninlet of the VTC-CAC, a hinged gate positioned across an opening of theintegrated bypass, and a threaded screw inserted through both thesliding gate and the hinged gate, and a stepper motor coupled to thethreaded screw to drive rotation of the threaded screw. In a firstexample of the VTC-CAC a brake drum is connected to the stepper motor,the brake drum housing a coil spring and a brake band surrounding thecoil spring. A second example of the VTC-CAC optionally includes thefirst example and further includes wherein the coil spring is adapted toincrease in tension when driven by the stepper motor rotating thethreaded screw in a first rotational direction, and wherein the brakeband is configured to maintain tension of the coil spring when thestepper motor is deactivated. A third example of the VTC-CAC optionallyincludes one or more of the first and second examples, and furtherincludes wherein rotating the threaded screw in the first rotationaldirection drives a linear movement of the sliding gate across theopenings of the cooling channels towards the bypass and simultaneouslydrives pivoting of the hinged gate to increase the opening of thebypass. A fourth example of the VTC-CAC optionally includes one or moreof the first through third examples, and further includes, wherein thethreaded screw has a first portion with a first pitch size that engageswith the sliding gate and a second portion with a second pitch size thatengages with the hinged gate. A fifth example of the VTC-CAC optionallyincludes one or more of the first through fourth examples, and furtherincludes, wherein the first pitch size is different from the secondpitch size so that the sliding gate travels a greater distance per turnof the threaded screw than the hinged gate. A sixth example of theVTC-CAC optionally includes one or more of the first through fifthexamples, and further includes, wherein the hinged gate has a threadedinsert held within a spherical bearing, the threaded insert adapted withthreading to mate with the second pitch size of the second portion ofthe threaded screw to translate rotation of the threaded screw into apivoting of the hinged gate while rotation of the spherical bearingaccommodates a change in angle of the hinged gate with respect to thethreaded screw. A seventh example of the VTC-CAC optionally includes oneor more of the first through sixth examples, and further includes,wherein the sliding gate has a threaded insert adapted with threading tomate with the first pitch size of the first portion of the threadedscrew and engages with the threaded screw to translate rotation of thethreaded screw into a linear motion of the sliding gate. A eighthexample of the VTC-CAC optionally includes one or more of the firstthrough seventh examples, and further includes, wherein the sliding gateincludes a plurality of stacked sections, each section of the pluralityof stacked sections configured with smaller dimensions than an adjacentsection below so that each section nests within and slides in and out ofthe adjacent section below. A ninth example of the VTC-CAC optionallyincludes one or more of the first through eighth examples, and furtherincludes, wherein a top section of the plurality of sections includeshigh temperature bearings, the high temperature bearings adapted toconstrain motion of the sliding gate along the openings of the coolingchannels and maintain a sealing contact between the top section an uppersurface of the VTC-CAC.

As another embodiment, a method includes adjusting a first flow volumeof the VTC-CAC while also adjusting an intake air flow amount through anintegrated bypass of the VTC-CAC based on manifold charge temperature.In a first example of the method, adjusting the first flow volume andadjusting intake air flow amount comprise actuating a dual-gatemechanism of the VTC-CAC with a single actuation action to both adjustthe first flow volume and the intake air flow amount. A second exampleof the method optionally includes the first example and further includeswherein the VTC-CAC comprises a plurality of cooling channels, andwherein adjusting the first flow volume comprises adjusting a number ofcooling channels of the plurality of cooling channels fluidicallycoupled to an inlet of the VTC-CAC, and further comprising as the numberof cooling channels fluidically coupled to the intake passage decreases,increasing the intake air flow amount through the integrated bypass ofthe VTC-CAC. A third example of the method optionally includes one ormore of the first and second examples and further includes whereinadjusting the number of cooling channels comprises adjusting a positionof a sliding gate of the dual-gate mechanism by rotating a threadedscrew that engages a threaded insert disposed in the sliding gate. Afourth example of the method optionally one or more of the first throughthird examples, and further includes wherein increasing the intake airamount bypassing the cooling channels comprises adjusting a position ofa hinged gate of the dual-gate mechanism by rotating the threaded screwthat engages a threaded insert and a spherical bearing disposed in thehinged gate.

In another representation, a method for controlling a manifold chargetemperature includes adjusting a position of a dual-gate mechanism of avariable thermal capacity charge air cooler (VTC-CAC) based on MCT,including increasing the MCT by activating a stepper motor coupled tothe dual-gate mechanism to move a sliding gate of the dual-gatemechanism in a first direction along a plurality of cooling channels ofthe VTC-CAC and open a hinged gate of the dual-gate mechanism, andflowing intake air though only a subset of the plurality of coolingchannels and through an integrated bypass of the VTC-CAC, responsive toa decrease in the MCT below a first threshold, and decreasing the MCT bydeactivating the stepper motor and actuating a solenoid, coupled to thestepper motor, to move the sliding gate in a second direction and closethe hinged gate, and flowing intake air through each cooling channel andnot through the integrated bypass responsive to an increase in the MCTabove a second threshold. In a first example of the method, adjusting aposition of the dual-gate mechanism further comprises rotating athreaded screw that engages with threaded inserts disposed in both thesliding gate and the hinged gate. A second example of the methodoptionally includes the first example, and further includes adjustingthe dual-gate mechanism to flow intake air through each cooling channeland closing the hinged gate when degradation of the stepper motor isdetected.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1. A cooling system of an engine, comprising: an intake passageconfigured to deliver boosted air to an intake manifold of the engine; acharge air cooler adapted to received boosted air from the intakepassage via an inlet and return boosted air to the intake passage via anoutlet, the charge air cooler comprising an integrated bypass, aplurality of cooling channels, and a dual-gate mechanism including afirst gate dividing the integrated bypass from the plurality of coolingchannels and a second gate dividing the plurality of cooling channelsinto open channels and blocked channels, the blocked channelsfluidically blocked from receiving intake air.
 2. The cooling system ofclaim 1, wherein the inlet is arranged in a first header tank and theoutlet is arranged in a second header tank that is positioned at anopposite end from the first header tank of the charge air cooler, andwherein the plurality of cooling channels and the integrated bypass eachfluidly couple the first header tank to the second header tank.
 3. Thecooling system of claim 2, wherein the dual-gate mechanism is positionedin the first header tank, and wherein the engine is coupled in ahybrid-electric vehicle powertrain.
 4. The cooling system of claim 3,further comprising a stepper motor configured to actuate the dual-gatemechanism and drive simultaneous movement of the first gate and thesecond gate, the stepper motor arranged external to the first headertank.
 5. The cooling system of claim 2, wherein the second gate extendsalong an entirety of the first header tank in a first direction from theplurality of cooling channels to a top of the first header tank and in asecond direction from a first side of the first header tank to a secondside of the first header tank, and the open channels include eachcooling channel on a hot side of the first header tank and the blockedchannels include each cooling channel on a cool side of the first headertank, a boundary between the hot side of the first header tank and thecool side of the first header tank defined by the second gate, the inletpositioned on the hot side of the first header tank, and wherein thesecond gate is configured to move laterally in the first header tank tosimultaneously adjust a number of cooling channels comprising the openchannels and a number cooling channels comprising the blocked channels.6. A variable thermal capacity charge air cooler (VTC-CAC), comprising:an integrated bypass; a plurality of cooling channels, arranged parallelwith and adjacent to the bypass; a dual-gate mechanism configured with asliding gate positioned in a first header tank that fluidically couplesopenings of the cooling channels to an inlet of the VTC-CAC, a hingedgate positioned across an opening of the integrated bypass, and athreaded screw inserted through both the sliding gate and the hingedgate; and a stepper motor coupled to the threaded screw to driverotation of the threaded screw.
 7. The VTC-CAC of claim 6, furthercomprising a brake drum connected to the stepper motor, the brake drumhousing a coil spring and a brake band surrounding the coil spring. 8.The VTC-CAC of claim 7, wherein the coil spring is adapted to increasein tension when driven by the stepper motor rotating the threaded screwin a first rotational direction, and wherein the brake band isconfigured to maintain tension of the coil spring when the stepper motoris deactivated.
 9. The VTC-CAC of claim 8, wherein rotating the threadedscrew in the first rotational direction drives a linear movement of thesliding gate across the openings of the cooling channels towards thebypass and simultaneously drives pivoting of the hinged gate to increasethe opening of the bypass.
 10. The VTC-CAC of claim 6, wherein thethreaded screw has a first portion with a first pitch size that engageswith the sliding gate and a second portion with a second pitch size thatengages with the hinged gate.
 11. The VTC-CAC of claim 10, wherein thefirst pitch size is different from the second pitch size so that thesliding gate travels a greater distance per turn of the threaded screwthan the hinged gate.
 12. The VTC-CAC of claim 11, wherein the hingedgate has a threaded insert held within a spherical bearing, the threadedinsert adapted with threading to mate with the second pitch size of thesecond portion of the threaded screw to translate rotation of thethreaded screw into a pivoting of the hinged gate while rotation of thespherical bearing accommodates a change in angle of the hinged gate withrespect to the threaded screw.
 13. The VTC-CAC of claim 11, wherein thesliding gate has a threaded insert adapted with threading to mate withthe first pitch size of the first portion of the threaded screw andengages with the threaded screw to translate rotation of the threadedscrew into a linear motion of the sliding gate.
 14. The VTC-CAC of claim6, wherein the sliding gate includes a plurality of stacked sections,each section of the plurality of stacked sections configured withsmaller dimensions than an adjacent section below so that each sectionnests within and slides in and out of the adjacent section below. 15.The VTC-CAC of claim 14, wherein a top section of the plurality ofsections includes high temperature bearings, the high temperaturebearings adapted to constrain motion of the sliding gate along theopenings of the cooling channels and maintain a sealing contact betweenthe top section an upper surface of the VTC-CAC.
 16. A method for avariable thermal capacity charge air cooler (VTC-CAC), comprising:adjusting a first flow volume of the VTC-CAC while also adjusting anintake air flow amount through an integrated bypass of the VTC-CAC basedon manifold charge temperature.
 17. The method of claim 16, wherein theadjusting of the first flow volume and the adjusting of intake air flowamount comprise actuating a dual-gate mechanism of the VTC-CAC with asingle actuation action to both adjust the first flow volume and theintake air flow amount.
 18. The method of claim 17, wherein the VTC-CACcomprises a plurality of cooling channels, and wherein adjusting thefirst flow volume comprises adjusting a number of cooling channels ofthe plurality of cooling channels fluidically coupled to an inlet of theVTC-CAC, and further comprising as the number of cooling channelsfluidically coupled to the intake passage decreases, increasing theintake air flow amount through the integrated bypass of the VTC-CAC. 19.The method of claim 18, wherein adjusting the number of cooling channelscomprises adjusting a position of a sliding gate of the dual-gatemechanism by rotating a threaded screw that engages a threaded insertdisposed in the sliding gate.
 20. The method of claim 19, whereinincreasing the intake air amount bypassing the cooling channelscomprises adjusting a position of a hinged gate of the dual-gatemechanism by rotating the threaded screw that engages a threaded insertand a spherical bearing disposed in the hinged gate.